Method and apparatus for uplink transmission in wireless communication system

ABSTRACT

A communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT) are provided, which may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. An uplink transmission method is provided, which can increase an uplink coverage through improvement of reception reliability of uplink control information and data information.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of prior application Ser. No.16/054,504, filed on Aug. 3, 2018, which is based on and claims priorityunder 35 U.S.C. § 119(a) of a Korean patent application number10-2017-0101478, filed on Aug. 10, 2017, in the Korean IntellectualProperty Office, the disclosure of which is incorporated by referenceherein in its entirety.

BACKGROUND 1. Field

The disclosure relates to a communication system. More particularly, thedisclosure relates to a method and an apparatus by a terminal for uplinktransmission in a communication system.

2. Description of the Related Art

To meet the demand for wireless data traffic having increased sincedeployment of fourth generation (4G) communication systems, efforts havebeen made to develop an improved fifth generation (5G) or pre-5Gcommunication system. Therefore, the 5G or pre-5G communication systemis also called a ‘Beyond 4G Network’ or a ‘Post long term evolution(LTE) System’. The 5G communication system is considered to beimplemented in higher frequency millimeter wave (mmWave) bands, e.g., 60GHz bands, so as to accomplish higher data rates. To decreasepropagation loss of the radio waves and increase the transmissiondistance, the beamforming, massive multiple-input multiple-output(MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beamforming, large scale antenna techniques are discussed in 5Gcommunication systems. In addition, in 5G communication systems,development for system network improvement is under way based onadvanced small cells, cloud radio access networks (RANs), ultra-densenetworks, device-to-device (D2D) communication, wireless backhaul,moving network, cooperative communication, coordinated Multi-Points(CoMP), reception-end interference cancellation and the like. In the 5Gsystem, Hybrid FSK and QAM Modulation (FQAM) and sliding windowsuperposition coding (SWSC) as an advanced coding modulation (ACM), andfilter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA),and sparse code multiple access (SCMA) as an advanced access technologyhave been developed.

The Internet, which is a human centered connectivity network wherehumans generate and consume information, is now evolving to the internetof things (IoT) where distributed entities, such as things, exchange andprocess information without human intervention. The internet ofeverything (IoE), which is a combination of the IoT technology and theBig Data processing technology through connection with a cloud server,has emerged. As technology elements, such as “sensing technology”,“wired/wireless communication and network infrastructure”, “serviceinterface technology”, and “Security technology” have been demanded forIoT implementation, a sensor network, a machine-to-machine (M2M)communication, machine type communication (MTC), and so forth have beenrecently researched. Such an IoT environment may provide intelligentInternet technology services that create a new value to human life bycollecting and analyzing data generated among connected things. IoT maybe applied to a variety of fields including smart home, smart building,smart city, smart car or connected cars, smart grid, health care, smartappliances and advanced medical services through convergence andcombination between existing information technology (IT) and variousindustrial applications.

In line with this, various attempts have been made to apply 5Gcommunication systems to IoT networks. For example, technologies such asa sensor network, MTC, and M2M communication may be implemented bybeamforming, MIMO, and array antennas. Application of a cloud RAN as theabove-described Big Data processing technology may also be considered tobe as an example of convergence between the 5G technology and the IoTtechnology.

On the other hand, in order to solve the cell radius reduction problemdue to reduction of the radio-wave propagation distance as describedabove, discussions on supplementary uplink (SUL) operations are inprogress. A 5G system (hereinafter referred to as “new radio (NR)system”) has a separate downlink/uplink band (in case of a frequencydivision duplex (FDD) system) operating the NR or a time division duplex(TDD) band operating the NR, and can share an uplink with the 4G systemin the related art. Accordingly, from the viewpoint of the NR system,the uplink that is shared with the 4G system may be considered as anadditional uplink, and such an additional uplink is called a SUL. Sincethe SUL operates at a center frequency that is lower than that of the NRband, it is possible to extend an uplink coverage of the NR system.

Since such a scenario does not exist in the 4G system in the relatedart, any operation method of a terminal and a base station in such ascenario has not been defined, and thus it is necessary to define suchan operation method.

The above information is presented as background information only toassist with an understanding of the disclosure. No determination hasbeen made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the disclosure.

SUMMARY

Aspects of the disclosure are to address at least the above-mentionedproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the disclosure is to providea method and an apparatus for operations of a terminal and a basestation for uplink transmission in a wireless communication system.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

In accordance with an aspect of the disclosure, a method by a terminalfor performing a random access is provided. The method includesreceiving information for performing the random access from a basestation, determining a frequency band to perform the random accessbetween first and second frequency bands based on the information forperforming the random access, and transmitting a preamble through thedetermined frequency band.

Determining the frequency band may include measuring a reference signalreceived power (RSRP) received from the base station, comparing the RSRPwith a threshold value included in the information for performing therandom access, determining the first frequency band as the frequencyband for performing the random access if the RSRP is smaller than thethreshold value, and determining the second frequency band as thefrequency band for performing the random access if the RSRP is equal toor larger than the threshold value.

Transmitting the preamble may include identifying a target receivedpower parameter of the preamble corresponding to the first frequencyband from the information for performing the random access if the RSRPis smaller than the threshold value, and transmitting the preamblethrough the first frequency band based on the target received powerparameter of the preamble corresponding to the first frequency band.

Transmitting the preamble may include identifying a target receivedpower parameter of the preamble corresponding to the second frequencyband from the information for performing the random access if the RSRPis equal to or larger than the threshold value, and transmitting thepreamble through the second frequency band based on the target receivedpower parameter of the preamble corresponding to the second frequencyband.

The first frequency band may be lower than the second frequency band.

The method may further include receiving information on transmission ofa physical uplink control channel (PUCCH) from the base station throughterminal-specific radio resource control (RRC) signaling, andtransmitting the PUCCH through the first or second frequency band basedon the information on the transmission of the PUCCH.

In accordance with another aspect of the disclosure, a method by a basestation for performing a random access is provided. The method includesgenerating information for performing the random access in a first orsecond frequency band, transmitting the generated information to aterminal, and receiving a preamble for performing the random accessthrough the determined frequency band based on the generatedinformation.

The method may further include transmitting to the terminal informationon a frequency band related to transmission of a physical uplink controlchannel (PUCCH) through terminal-specific radio resource control (RRC)signaling.

In accordance with another aspect of the disclosure, a terminal isprovided. The terminal includes a transceiver, and a controllerconfigured to control the transceiver to receive information forperforming a random access from a base station, determine a frequencyband to perform the random access between first and second frequencybands based on the information for performing the random access, andcontrol the transceiver to transmit a preamble through the determinedfrequency band.

The controller may be configured to measure a reference signal receivedpower (RSRP) received from the base station, compare the RSRP with athreshold value included in the information for performing the randomaccess, determine the first frequency band as the frequency band forperforming the random access if the RSRP is smaller than the thresholdvalue, and determine the second frequency band as the frequency band forperforming the random access if the RSRP is equal to or larger than thethreshold value.

The controller may be configured to identify a target received powerparameter of the preamble corresponding to the first frequency band fromthe information for performing the random access if the RSRP is smallerthan the threshold value, and control the transceiver to transmit thepreamble through the first frequency band based on the target receivedpower parameter of the preamble corresponding to the first frequencyband.

The controller may be configured to identify a target received powerparameter of the preamble corresponding to the second frequency bandfrom the information for performing the random access if the RSRP isequal to or larger than the threshold value, and control the transceiverto transmit the preamble through the second frequency band based on thetarget received power parameter of the preamble corresponding to thesecond frequency band.

The controller may be configured to control the transceiver to receiveinformation on transmission of a physical uplink control channel (PUCCH)from the base station through terminal-specific radio resource control(RRC) signaling, and control the transceiver to transmit the PUCCHthrough the first or second frequency band based on the information onthe transmission of the PUCCH.

In accordance with another aspect of the disclosure, a base station isprovided. The base station includes a transceiver, and a controllerconfigured to generate information for performing the random access in afirst or second frequency band, control the transceiver to transmit thegenerated information to a terminal, and control the transceiver toreceive a preamble for performing the random access through thefrequency band determined based on the generated information.

The controller may be configured to control the transceiver to transmitto the terminal information on a frequency band related to transmissionof a physical uplink control channel (PUCCH) through terminal-specificradio resource control (RRC) signaling.

According to the aspects of the disclosure, the method for uplinktransmission can improve reception reliability of uplink controlinformation and data information, and thus can increase the uplinkcoverage.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a diagram explaining an example of carrier aggregation (CA) ina frequency division duplex (FDD) system of a long term evolutionadvanced (LTE-A) in the according to the related art;

FIG. 2A is a diagram explaining an example of a supplementary uplink(SUL) operation scenario in a new radio (NR) FDD system according tovarious embodiments of the disclosure;

FIG. 2B is a diagram explaining an example of a SUL operation scenarioin an NR TDD system according to various embodiments of the disclosure;

FIG. 3 is a diagram illustrating an example of a procedure by a basestation and a terminal for performing a random access in SUL operationscenarios according to various embodiments of the disclosure;

FIG. 4A is a diagram illustrating an example of a terminal operation fora terminal initial access in SUL operation scenarios according tovarious embodiments of the disclosure;

FIG. 4B is a diagram illustrating an example of a base station operationfor a terminal initial access in SUL operation scenarios according tovarious embodiments of the disclosure;

FIG. 5A is a diagram illustrating another example of a terminaloperation for a terminal initial access in SUL operation scenariosaccording to various embodiments of the disclosure;

FIG. 5B is a diagram illustrating another example of a base stationoperation for a terminal initial access in SUL operation scenariosaccording to various embodiments of the disclosure;

FIG. 6A is a diagram illustrating still another example of a terminaloperation for a terminal initial access in SUL operation scenariosaccording to various embodiments of the disclosure;

FIG. 6B is a diagram illustrating still another example of a basestation operation for a terminal initial access in SUL operationscenarios according to various embodiments of the disclosure;

FIG. 7A is a diagram illustrating yet still another example of aterminal operation for a terminal initial access in SUL operationscenarios according to various embodiments of the disclosure;

FIG. 7B is a diagram illustrating yet still another example of a basestation operation for a terminal initial access in SUL operationscenarios according to various embodiments of the disclosure;

FIG. 8A is a diagram illustrating an example of a media accesscontrol-control element (MAC CE) for activation/deactivation of a SUL inSUL operation scenarios according to various embodiments of thedisclosure;

FIG. 8B is a diagram illustrating an example of a MAC CE fortransmission of a path loss value measured by a base station in a SUL inSUL operation scenarios according to various embodiments of thedisclosure;

FIG. 8C is a diagram illustrating an example of a MAC CE foractivation/deactivation of a SUL and for transmission of a path lossvalue measured by a base station in an activated SUL in SUL operationscenarios according to various embodiments of the disclosure;

FIG. 9 is a diagram illustrating an example of a procedure in which abase station transmits to a terminal offset information between adownlink path loss value measured by the terminal and an uplink pathloss value measured by the base station according to various embodimentsof the disclosure;

FIG. 10 is a block diagram illustrating a structure of a terminalaccording to various embodiments of the disclosure; and

FIG. 11 is a block diagram illustrating a structure of a base stationaccording to various embodiments of the disclosure.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components, and structures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thedisclosure. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of thedisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of thedisclosure is provided for illustration purpose only and not for thepurpose of limiting the disclosure as defined by the appended claims andtheir equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

FIG. 1 is a diagram explaining an example of carrier aggregation (CA) ina frequency division duplex (FDD) system of an LTE-A in the related art.

Referring to FIG. 1, it is exemplified that a downlink is composed of Ncomponent carriers (CCs), and an uplink is composed of K CCs. Such a CAtechnology can support a large bandwidth through aggregation of two ormore carriers having small-sized bandwidths, and thus it can heightenthe data rate and can efficiently use frequency spectrums. For example,the maximum bandwidth of 100 MHz can be supported through aggregation offive CCs each having the maximum bandwidth of 20 MHz.

On the other hand, CA introduced in LTE Rel-10 (Release-10) has alimitation that it should support a terminal 120 of an LTE version inthe related art (e.g., a Rel-8/Rel-9 terminal). For this, in LTE Rel-10CA, a physical broadcast channel (PBCH) including a synchronizationsignal, such as a primary synchronization signal (PSS) and a secondarysynchronization signal (SSS), and system information is transmitted fromall CCs. That is, since the Rel-8/9 terminal does not have the CAfunction, downlink synchronization is preformed using one downlink CCamong PSS/SSS and PBCHs transmitted from all CCs, such as CC #1 to CC #N, and the random access is performed through the uplink CCcorresponding to the downlink CC having performed the downlinksynchronization, so that the terminal can access the corresponding cell.That is, from the viewpoint of a Rel-8/9 terminal, CC #1 to CC # N maybe seen as different Cell #1 to Cell # N. In the same manner, in orderto support compatibility (backward compatibility) with a previousrelease terminal, a terminal supporting Rel-10 CA functions can alsoaccess the cell through a specific CC through reception of PSS/SSS andPBCH transmitted through all CCs, such as CC #1 to CC # N. The terminalsupporting Rel-10 CA functions accessing through one CC consider thecorresponding CC as the primary CC (PCC), and the remaining CCsexcluding the PCC may be candidates of the secondary CC (SCC). A basestation can configure how many CCs among the SCC candidates will beactual SCCs of a specific terminal. Further, the terminal havingaccessed the cell through the PCC can perform change of the PCC accessedthrough a handover process.

Although FIG. 1 illustrates the FDD system, the CA can also be appliedto a TDD system in the same manner. However, in the TDD system, asillustrated in FIG. 1, the downlink frequency band and the uplinkfrequency band are not discriminated from each other. That is, if it isassumed that the TDD frequency band is composed of N CCs, downlinksubframes and uplink subframes in the respective CCs may exist inaccordance with TDD DL/UL configurations. Further, although notillustrated in FIG. 1, the CCs defined for the FDD system and the CCsdefined for the TDD system can perform the CA.

FIG. 2A is a diagram explaining an example of a SUL scenario in an NRFDD system according to various embodiments of the disclosure.

A system having an NR DL band and an NR UL band may operate a SUL at acenter frequency that is lower than that of the NR band. In this case,the system disclosed in FIG. 2A is different from the system disclosedin FIG. 1 on the point that there is no downlink band corresponding tothe SUL. Accordingly, the terminal may perform downlink synchronizationand may acquire system information using PSS/SSS and PBCH transmitted onthe NR DL band. The uplink synchronization (i.e., random access) may beperformed using the NR UL band or the SUL.

FIG. 2B is a diagram explaining an example of a SUL operation scenarioin an NR TDD system according to various embodiments of the disclosure.

The 5G TDD system may perform downlink and uplink transmission/receptionon an NR TDD band. In addition, the 5G TDD system may perform uplinktransmission on a separate SUL frequency band f_(SUL). In the systemdisclosed in FIG. 2B, in the same manner as the system disclosed in FIG.2A, the terminal may perform downlink synchronization and may acquiresystem information using PSS/SSS and PBCH transmitted on the NR TDDband. The uplink synchronization (i.e., random access) may be performedusing uplink subframes of the NR TDD band or a separate SUL frequencyband. That is, the SUL frequency band f_(SUL) is used only for uplinktransmission of the terminal and uplink reception of the base station,but is not used for downlink reception of the terminal and downlinktransmission of the base station.

Although not illustrated in FIG. 2A, each of the NR DL band and the NRUL band may be composed of two or more CCs as illustrated in FIG. 1.Further, although not illustrated in FIG. 2B, the NR TDD band may becomposed of two or more CCs as illustrated in FIG. 1. In FIG. 1, a pairis formed between the CC on which the terminal performs downlinksynchronization and the CC on which the terminal performs uplinksynchronization, whereas in FIGS. 2A and 2B, there is no DL band or DLsubframe corresponding to the SUL, and thus the DL band or the DLsubframe that forms a pair with the SUL does not exist. Accordingly, itmay be necessary to define operations of the base station and theterminal on whether the terminal performs the uplink synchronizationthrough the NR UL band (or NR UL subframe) or the SUL band (or SULsubframe). The disclosure proposes the operations of the base stationand the terminal to operate the SUL.

The DL band may be the term used in the FDD system, and the DL subframemay be the term used in the TDD system or FDD system. However, in thedisclosure, it is predefined that the NR DL band may call one of the NRDL band and the NR DL subframe.

Option 1) The base station transmits a random access parameter for oneband between the NR UL band and the SUL band.

The base station may transmit a random access parameter for one bandbetween the NR UL band and the SUL band, and the terminal may perform arandom access for one band between the NR UL band and the SUL band usingthe random access parameter transmitted by the base station.Accordingly, the base station may expect to receive the random accesspreamble from the band configured by the base station itself, and maymonitor only the random access preamble on the corresponding band.

As an example, the base station may transmit the random access parameterfor the NR UL band or the SUL band to the terminal through systeminformation (e.g., remaining minimum system information (RMSI)) or othersystem information (OSI). In this case, the random access parameter mayinclude the following examples, and the following parameters arecommonly existing parameters regardless of whether the base stationtransmits the random access parameter for the NR UL band or the randomaccess parameter for the SUL band. However, since the NR UL band and theSUL band may have quite different channel characteristics, therespective parameters may have different values depending on whether thebase station transmits the random access parameter for the NR UL band orthe random access parameter for the SUL band.

Random Access Parameter

This is time resource information for transmitting the random accesspreamble, and may include a system frame number for transmitting therandom access preamble, subframe number (or slot number), random accesspreamble format, density of the random access preamble (in case of a TDDsystem), and parameter for notifying of a version index of the randomaccess preamble (prach-ConfigurationIndex).

Information indicating the location of a frequency resource fortransmitting the random access preamble as the number of resource blocks(RBs) at the center frequency at which the random access preamble istransmitted (prach-FrequencyOffset).

Sequence information on the random access preamble, and informationnotifying of a logical root sequence number of a root Zadoff-Chusequence used for the random access preamble (rootSequencelndex).

Maximum number of transmissions of the random access preamble(preambleTransMax).

Window size for receiving a random access response (RAR)(ra-ResponseWindowSize).

Transmitted power increment size of the random access preamble(powerRampingStep).

Initial random access preamble transmitted power(preambleInitialReceivedTargetPower).

Subcarrier spacing that can be used to transmit the random accesspreamble (subcarrier spacing).

Uplink waveform information used for Msg.3 transmission (i.e.,information notifying whether the information is DFT-S-OFDM or CP-OFDM).

In order to indicate a band on which the terminal can perform the randomaccess in addition to the random access parameter, the base station mayinclude at least one of the following random access parameters in RMSIor OSI information.

Information on the center frequency of the uplink band for performingthe random access preamble: for example, information on f_(NR-UL)corresponding to the NR UL band or f_(UL) corresponding to the SUL band.If the corresponding information is included, the terminal may performthe random access on the corresponding UL band (this is called{circumflex over (1)} implicit indication).

The 1-bit indication indicating whether the terminal performs the randomaccess on the NR UL band or the SUL (this is called {circumflex over(2)} explicit indication).

In case where the base station transmits to the terminal the randomaccess parameters on the SUL through the RMSI or OSI, the random accessparameter may include time/frequency resources for transmitting therandom access preamble on the SUL. In general, although the initialrandom access preamble (Msg.1) is transmitted from the uplink, this isperformed before the terminal acquires TA information, and thus theinitial random access preamble is transmitted without TA (i.e.,transmission is performed based on downlink timing of the terminal).However, since there is not downlink timing of the terminal for the NRDL band or the NR DL subframe on the SUL, the base station may transmitreference timing for the terminal to transmit Msg.1 to the SUL. Suchreference timing may be an offset between a specific NR DL subframe(e.g., subframe on which a PBCH is transmitted) and an SUL slot (orsubframe) on which Msg.1 is transmitted, or an offset between a specificNR system frame number (e.g., NR system frame number 0) acquired by theterminal through the NR DL band and the SUL slot (or subframe) on whichMsg.1 is transmitted.

-   -   As another example, the base station may not transmit to the        terminal separate information ({circumflex over (1)} as        described above) for the uplink band on which the random access        should be performed or separate indication ({circumflex over        (2)} as described above). In this case, the terminal may        transmit the random access preamble on the uplink band        pre-engaged with the base station (this is called {circumflex        over (3)} pre-configuration). For example, if the base station        and the terminal pre-engage to use the NR UL band as a default        band for transmitting the random access preamble, the terminal        may transmit the random access preamble through the NR UL band.        Further, the base station and the terminal may pre-engage to use        the SUL band as a default band for transmitting the random        access preamble of the terminal. In this case, the base station        may transmit only the random access parameter for the default        band through the RMSI or OSI. Further, the terminal may transmit        the random access preamble, uplink data, and control        information/control signals on the default uplink band engaged        with the base station until the terminal receives an additional        command for band switching from the base station.    -   As still another example, the NR DL band or the NR UL band used        by the base station and the terminal may be mapped to a specific        SUL band. That is, if the terminal acquires the center frequency        information of an NR cell downlink band accessed by the terminal        itself through a synchronization signal and system information        transmitted to the NR DL band, the terminal may automatically        acquire frequency information of the SUL band (e.g., at least        one of SUL band center frequency and bandwidth information).        Further, if the terminal acquires frequency information of an NR        cell uplink band accessed by the terminal itself (e.g., NR UL        band center frequency and bandwidth information) through the        synchronization signal and the system information transmitted on        the NR DL band, the terminal may automatically acquire the        frequency information of the SUL band (e.g., at least one of SUL        band center frequency and bandwidth information). Further, the        uplink frequency information of the NR cell and the frequency        information on the SUL band may be mapped to the downlink        frequency information of the NR cell acquired by the terminal.        Accordingly, the terminal may perform the random access on the        NR UL band or SUL by the method of {circumflex over (1)},        {circumflex over (2)}, or {circumflex over (3)} as described        above using the frequency information of the NR UL band acquired        by the terminal itself or the frequency information of the SUL        band.

In option 1 as described above, the terminal can perform the randomaccess on only one of the NR UL band and the SUL band. Accordingly, thebase station may expect that the random access preamble of the terminalis to be transmitted only on the band configured by the base stationitself, and may monitor only the corresponding band. Further, since thebase station transmits only the random access information on one of thetwo bands, overhead of the system information transmission can bereduced. However, if the number of terminals performing the randomaccess on one band configured by the base station is increased, it isnecessary to properly decentralize the terminals into other bands forload balancing. Accordingly, operations of the base station and theterminal to switch the bands capable of performing the random access maybe necessary. The following options may be considered as band switchingoperations during the operation as option 1 as described above.

Option 1-A) In accordance with the option 1 as described above, theterminal may perform the random access on one of the NR UL band and theSUL band. The base station may transmit parameters for other bandsexcluding the band on which the random access has been performed throughseparate signaling after the random access procedure of the terminal.For example, if the random access is performed on the NR UL band, theparameters for the uplink transmission on the SUL may be transmitted tothe terminal through separate signaling. Further, if the random accessis performed on the SUL, the parameters for the uplink transmission onthe NR UL band may be transmitted to the terminal through separatesignaling.

-   -   As an example, consider FIG. 3. FIG. 3 is a diagram illustrating        an example of a procedure by a base station and a terminal for        performing a random access in SUL operation scenarios according        to various embodiments of the disclosure. As shown in FIG. 3,        the base station may transmit the previously exemplified random        access parameters that can be transmitted on the NR UL band        through the RMSI or OSI in operation 302. After performing the        downlink synchronization on the NR DL band in operation 304, the        terminal may receive information on the random access parameters        through the RMSI or OSI, and may perform the random access        procedure in operation 306. After completing the random access        procedure and RRC connection setup in operation 308, the        terminal may receive information on the SUL band from the base        station through UE-specific RRC signaling in operation 310. In        this case, the terminal may perform capability negotiation on        whether the terminal itself supports the SUL band with the base        station. The information on the SUL band transmitted by the base        station through the UE-specific RRC signaling may include at        least one of SUL band center frequency and bandwidth, timing        advance (TA) information and subcarrier spacing information for        transmitting uplink data and control information/control signal        on the SUL, and information for the random access preamble        (contention-free random access) on the SUL. In this case, the        contention-free random access on the SUL band may be triggered        by an order of the base station (e.g., through downlink control        information (DCI) of a physical downlink control channel        (PDCCH)), and may be used for the base station to acquire TA        information of the terminal having performed the RRC connection        (in a case where the TA timer expires and it is necessary to        additionally acquire the TA information although the terminal is        in an RRC connection state), or may be used for the base station        to estimate an uplink path loss value on the SUL. On the other        hand, in case of requesting switching of the uplink band, the        base station may deactivate the band being used by the terminal,        and may activate another band in operation 312. Further, the        base station may make the band being used by the terminal be        used as it is, and may additionally activate the other band.        Such activation/deactivation may be transmitted from the base        station to the terminal through MAC control element (CE), L1        signaling (e.g., DCI), or a combination thereof. For example, in        FIG. 3, the base station may deactivate the NR UL band on which        the terminal has performed the random access, and may activate        the SUL band.    -   As another example, although not illustrated in FIG. 3, if the        random access is performed on the SUL in accordance with option        1 as described above, the base station may transmit information        on the NR UL band through the UE-specific RRC signaling. In this        case, information on the NR UL band may include at least one of        NR UL band center frequency and bandwidth, timing advance (TA)        information for uplink data/control information/control signal        transmission on the NR UL band, information on subcarrier        spacing and beams, and information for indicating to the base        station whether the random access preamble (contention-free        random access preamble) has been transmitted on the NR UL band        or whether the downlink beam has failed. In this case, the        random access on the NR UL band may be triggered by the order of        the base station (e.g., through the DCI) of the physical        downlink control channel (PDCCH)), and may be used for the base        station to acquire the timing advance (TA) information that may        differ from each other for beams used by the terminal. Further,        the random access may be used for the base station to estimate        the uplink path loss value of the NR UL band. Further, if the        base station requests switching of the uplink band, the base        station may deactivate the SUL band through MAC control element        (CE), L1 signaling (e.g., DCI), or a combination thereof, and        may activate the NR UL band. Further, the base station may make        the SUL band on which the random access procedure has been        performed be used as it is, and may additionally activate the NR        UL band.

Option 1-B) By the method mentioned in option 1 as described above(e.g., {circumflex over (1)} implicit indication, {circumflex over (2)}explicit indication, and {circumflex over (3)} pre-configuration), thebase station may order the terminal to perform the random access on theNR UL band or on the SUL. Accordingly, the terminal may perform therandom access on one of the NR UL band and the SUL band. In this case,unlike option 1-A as described above, the base station may command bandswitching through random access response (RAR) grant transmitted on thePDCCH or RAR (Msg.2) transmitted on the PDSCH as shown in FIGS. 4A and4B.

-   -   As an example, see FIG. 4A. FIG. 4A is a diagram illustrating an        example of a terminal operation for a terminal initial access in        SUL operation scenarios according to various embodiments of the        disclosure. As seen in FIG. 4A, if the base station configures        to perform the random access on the NR UL band in accordance        with option 1 as described above in operations 402 and 404, the        terminal transmits the random access preamble (Msg.1) on the NR        UL band in operation 406. The terminal having transmitted Msg.1        attempts reception of the RAR during RAR reception window        (ra-ResponseWindowSize) configured by the base station through        the RMSI or OSI (receive Msg.2) in operation 408. The terminal        having not received Msg.2 in the corresponding window determines        whether the number of transmissions of Msg.1 reaches the maximum        value (or determines whether the number of retransmissions of        Msg.1 reaches the maximum value) in operation 410. If the number        of transmissions of Msg.1 has reached the maximum value, the        terminal ends the random access operation, and re-performs cell        search in operation 412. In this case, the maximum number of        transmissions of Msg.1 may be included in random access        parameter configuration of SIB or RMSI transmitted from the base        station to the terminal (preambleTransMax). When the terminal        retransmits Msg.1, the base station may increase transmitted        power of Msg.1 as much as the power ramping step size        (powerRampingStep) included in the ransom access parameter        configuration of SIB or RMSI in operation 414. On the other        hand, the terminal having succeeded in the Msg.2 reception may        receive a band switching command included in the RAR grant or        the RAR in operation 416. In this case, the base station may        command the band switching in an explicit or implicit method as        follows.

Explicit band switching command: The base station may set 1-bit fieldcommanding the band switching in the RAR grant or RAR message to “1”.The terminal having received this may transmit Msg.3 on another bandother than the band used for Msg.1 transmission in operation 418. Forexample, if the terminal transmits Msg.1 on the NR UL band, and receivesthe band switching command through the RAR grant or RAR message, theterminal can transmit Msg.3 on the SUL. An opposite case may also bepossible. On the other hand, if the base station commands the bandswitching through the RAR grant, the base station may transmit frequencyinformation of the band to be changed by the terminal through the RAR(Msg.2) (e.g., center frequency and bandwidth of the band to beswitched) and parameters for uplink transmission performed on the bandto be changed in operation 420. In this case, the parameters for theuplink transmission may include TA used for the terminal to performuplink transmission, parameters for calculating a transmitted powervalue of the terminal, and subcarrier spacing. As another example, thebase station may not command the band switching through 1-bit field ofthe RAR grant, but may command the band switching through MAC CEtransmitted to the RAR. In this case, the MAC CE may deactivate theuplink band used for Msg.1 transmission, and may activate the changeduplink band. That is, if Msg.1 is transmitted through the NR UL band,the base station may deactivate the NR UL band, and may activate the SULband. The terminal having received this may transmit Msg.3 on the SULband. An opposite case may also be possible. Even in case where the basestation commands the band switching through the MAC CE of the RAR, asdescribed above, the base station may transmit frequency information ofthe band to be changed by the terminal through the RAR (Msg.2) (e.g.,center frequency and bandwidth of the band to be switched) andparameters for uplink transmission performed on the band to be changed.

Implicit band switching command: Unlike the above-described example(1-bit field of the RAR grant or RAR message or the MAC CE of the RARexplicitly commands the band switching), the band switching can becommanded if a specific field of the RAR grant or RAR message is set toa specific value. As an example, if the field indicating resourceallocation information of the RAR is set to “00000 . . . 0” in the RARgrant, the terminal may determine that the base station has commandedthe band switching. On the other hand, if the base station includesfrequency information of a new band (e.g., center frequency andbandwidth of the band to be switched) and parameters for the uplinktransmission performed in the band to be change in the RAR message, theterminal may determine that the band switching has been commanded. Forexample, when the terminal accessing Msg.1 on the NR UL band receivesthe RAR, information on the SUL band may be included in the RAR message.In this case, the terminal may transmit Msg.3 on the SUL.

-   -   In the above-described examples, in case of transmitting initial        Msg.1 after acquiring the random access parameter transmitted        from the base station, the terminal should set the transmitted        power value for transmitting Msg. 1. In this case, the        transmitted power value for transmitting Msg.1 may be determined        by the terminal through mathematical expression 1 below.

P _(PRACH)=min{P _(CMAX)(i),PREAMBLE_RECEIVED_TARGET_POWER+PL}[dBm]  Mathematical expression 1

In the mathematical expression 1, P_(CMAX) (i) means the maximumtransmitted power value that the terminal can use in the i-th subframe(or slot). PREAMBLE_RECEIVED_TARGET_POWER is related to the transmittedpower value for initial random access preamble transmission(preambleInitialReceivedTargetPower) configured by the base stationthrough the RMSI or SIB and a power ramping step size. That is, it canbe expressed as “PREAMBLE_RECEIVED_TARGET_POWERpreambleInitialReceivedTargetPower+Delta_Preamble+(Preamble_transmission_counter−1)*powerRampingStep”.The term “Delta_Preamble” is an offset value in accordance with theformat of the random access preamble, and is a value pre-engaged betweenthe base station and the terminal. As an example, preamble format 0 andformat 1 may have an offset value of 0 dB, and preamble format 0 andformat 1 may have an offset value of −3 dB.

On the other hand, in the mathematical expression 1, PL is a downlinkpath loss value estimated by the terminal through a downlink signaltransmitted by the base station. As illustrated in FIGS. 2A and 2B,since the existence of the NR UL band corresponds to the existence ofthe NR DL band, it is possible to estimate the downlink path loss valuefor setting the transmitted power value of Msg.1 transmitted on the NRUL band using downlink signals transmitted to the NR DL band. However,since a downlink band corresponding to the SUL band does not exist, itis not possible to set the transmitted power value of Msg.1 using thedownlink path loss value when the terminal transmits Msg.1 to the SUL.To solve this problem, the base station may transmit the transmittedpower value that the terminal can use for transmission of Msg.1 or thepath loss value that the terminal can use for transmission of Msg.1through a master information block (MIB), RMSI, or OSI. As anotherexample, even if the terminal transmits Msg.1 on the SUL band, theterminal can set the transmitted power value of Msg.1 using the downlinkpath loss value estimated from the downlink signal of the NR DL band. Inthis case, the uplink path loss value of the SUL may be different fromthe downlink path loss value of the NR DL band, and in order tocompensate for this, the base station may transmit a specific offsetvalue to the terminal through the MIB, RMSI, or OSI.

In the above-described examples, if the terminal changes the band fromthe NR UL band to the SUL band, the terminal may transmit Msg.3 throughthe physical uplink shared channel (PUSCH) on the SUL band. In thiscase, the terminal may set the transmitted power value for transmittingMsg.3 as in mathematical expression 2 below.

P _(PUSCH)=min{P _(CMAX)(i),P _(0_PRE)+Δ_(PREAMBLE_Msg3)+Δ_(TF) +PL+ΔP_(rampup)+δ_(msg2)}[dBm]   Mathematical expression 2

In the mathematical expression 2, P_(CMAX) (i) means the maximumtransmitted power value that the terminal can use in the i-th subframe(or slot). P_(0_PRE) means preambleInitialReceivedTargetPower, andΔ_(PREAMBLE_Msg3) is another offset value related to the random accesspreamble format, and may be configured by the base station through theRMSI or other system information (OSI). Δ_(TF) is a parameter related tothe MCS of Msg.3, ΔP_(rampup) means a power ramping step size, andδ_(msg2) is a transmission power control (TPC) command transmitted fromthe RAR grant.

On the other hand, in the mathematical expression 2, PL is a downlinkpath loss value estimated by the terminal through a downlink signaltransmitted by the base station. As illustrated in FIGS. 2A and 2B,since the existence of the NR UL band corresponds to the existence ofthe NR DL band, it is possible to estimate the downlink path loss valuefor setting the transmitted power value of Msg.1 transmitted on the NRUL band using downlink signals transmitted to the NR DL band. However,since a downlink band corresponding to the SUL band does not exist, itis not possible to set the transmitted power value of Msg.3 using thedownlink path loss value when the terminal transmits Msg.3 to the SUL.To solve this problem, the base station may transmit the transmittedpower value that the terminal can use for transmission of Msg.3 or thepath loss value that the terminal can use for transmission of Msg.3through the RAR. As another example, even if the terminal transmitsMsg.3 on the SUL band, the terminal can set the transmitted power valueof Msg.3 using the downlink path loss value estimated from the downlinksignal of the NR DL band. In this case, the uplink path loss value ofthe SUL may be different from the path loss value of the NR DL bandestimated by the terminal to transmit Msg.1, and in order to compensatefor this, the base station may transmit a specific offset value throughthe RAR.

In the above-described examples, if the terminal changes the band fromthe NR UL band to the SUL band, the terminal may transmit Msg.3 throughthe physical uplink shared channel (PUSCH) on the SUL band. In thiscase, the terminal requires the TA value for transmitting Msg.3, and thebase station can transmit the TA value to the terminal through the RAR.In this case, the base station may reflect the timing offset between theNR UL band and the SUL in the TA value.

The operation of the base station for option 1-B is illustrated in FIG.4B. FIG. 4B is a diagram illustrating an example of a base stationoperation for a terminal initial access in SUL operation scenariosaccording to various embodiments of the disclosure. In FIG. 4B, the basestation transmits the random access parameter for one of the NR UL bandand the SUL band in operation 430. As an example, the base station maytransmit the random access parameter for the NR UL band. The basestation expects that Msg.1 of the terminal is to be transmitted to theNR UL band configured by the base station itself, and monitors thecorresponding band in operation 432. Further, the base station maydetermine whether the UL band (UL carrier) for the correspondingterminal to transmit Msg.3 has been changed in operation 434. As anexample, if the received power of Msg.1 transmitted by the terminal isequal to or smaller than the threshold value, the base station maydetermine that Msg.3 transmission of the corresponding terminal is to beperformed on the SUL. As another example, even if the received power ofMsg.1 transmitted from terminal-A is larger than the threshold value,the base station may determine to change the band for transmitting Msg.3of terminal-A for load balancing with other terminals transmitting therandom access preamble. The base station having determined to change theUL carrier (UL band) may transmit information on the changed band to theRAR grant and the RAR transmitted on the NR DL band in operation 436. Inthis case, information included in the RAR grant and RAR (Msg.2) is thesame as that in the above-described terminal operation. The terminalhaving received Msg.2 on the NR DL band transmits Msg.3 in accordancewith the band switching command included in the RAR grant and RAR(Msg.2). The base station may receive Msg.3 on the band commanded by thebase station itself in operation 438, and may transmit Msg.4 on the NRDL band in operation 440.

Option 1-C) By the method mentioned in option 1 as described above(e.g., {circumflex over (1)} implicit indication, {circumflex over (2)}explicit indication, and {circumflex over (3)} pre-configuration), thebase station may order the terminal to perform the random access on theNR UL band or on the SUL. Accordingly, the terminal may perform therandom access on one of the NR UL band and the SUL band. In this case,the terminal and the base station may operate through a combination ofthe option 1-A and option 1-B. More specifically, the terminal operatingin option 1-B may receive a command for changing the UL band throughUE-specific RRC signaling, MAC CE, or MAC message from the base stationas in option 1-A after the RRC connection setup. In this case, the ULband used by the terminal in the random access process may be differentfrom the UL band used for the random access or uplink data and controlinformation/control signal transmission after the RRC connection setup.

Option 2) Transmission of a random access parameter for both the NR ULband and the SUL band.

In option 1 as described above, the base station transmits random accessparameters of one of the NR UL band and the SUL. Unlike this, in option2, the base station simultaneously transmits random access parametersfor the NR UL band and random access parameters for the SUL band throughRMSI or OSI. The terminal having received this may perform the followingoperations. The random access parameter that the base station transmitsto the terminal through the RIVISI or OSI includes time/frequencyresources for transmitting the random access preamble on the SUL. Ingeneral, although initial random access preamble (Msg.1) is transmittedfrom the uplink, Msg.1 transmission is performed before the terminalacquires TA information, and thus the terminal may transmit Msg.1without TA (i.e., transmission is performed based on downlink timing ofthe terminal). However, since there is not downlink timing of theterminal for the NR DL band or the NR DL subframe on the SUL, the basestation may transmit reference timing for the terminal to transmit Msg.1to the SUL. Such reference timing may be an offset between a specific NRDL subframe (e.g., subframe on which a PBCH is transmitted) and an SULslot (or subframe) on which Msg.1 is transmitted, or an offset between aspecific NR system frame number (e.g., NR system frame number 0)acquired by the terminal through the NR DL band and the SUL slot (orsubframe) on which Msg.1 is transmitted.

Option 2-A) FIG. 5A is a diagram illustrating another example of aterminal operation for a terminal initial access in SUL operationscenarios according to various embodiments of the disclosure. As seen inFIG. 5, the terminal performs downlink synchronization and acquires NRsystem information through reception of PSS/SSS and PBCH transmitted onthe NR DL band in operation 502. Further, the terminal may acquirerandom access parameters through reception of RMSI or OSI transmitted onthe NR DL band in operation 504. In this case, the random accessparameters may include random access parameters for both the two bandsso that the terminal can respectively perform the random access on theNR UL band and the SUL band. The terminal having acquired the randomaccess parameters for the two bands may measure a reference signalreceived power (RSRP) of the NR DL band in operation 506. In this case,the RSRP may be a received signal strength of the SSS transmitted on theNR DL band, or an average value of the received signal strength of theSSS transmitted on the NR DL band and the received signal strength of ademodulation reference signal (DMRS) transmitted on the PBCH, or anaverage value of weighted sums. For example, “alpha” may be weighted onthe received signal strength of the SSS, “beta” may be weighted on thereceived signal strength of the DMRS transmitted on the NR DL band, andthe weighted received signal strengths are added together to obtain anaverage value thereof. In this case, the alpha and beta values may beconfigured by the base station through the RMSI or OSI, or may bepre-engaged between the base station and the terminal. The terminalhaving measured the RSRP of the NR DL band using one of theabove-described methods may compare the threshold value configured bythe base station with the RSRP value of the NR DL band measured by theterminal itself in operation 508. In this case, configuration of thethreshold value may be performed through the RMSI or OSI. That is, ifthe RSRP value of the NR DL band measured by the terminal is equal to orlarger than the threshold value configured by the base station, theterminal may transmit the random access preamble (Msg.1) on the NR ULband in operation 512. In this case, the terminal may calculate thetransmitted power value of Msg.1 through the mathematical expression 1in operation 510. On the other hand, if the RSRP value of the NR DL bandmeasured by the terminal is smaller than the threshold value configuredby the base station, the terminal may transmit Msg.1 on the SUL inoperation 516. The transmitted power value of Msg.1 transmitted on theSUL may be calculated by the terminal through the mathematicalexpression 1 in operation 514. In this case, parameter values forcalculating the transmitted power value of Msg.1 transmitted on the NRUL band and parameter values for calculating the transmitted power valueof Msg.1 transmitted on the SUL in the mathematical expression 1 may beequal to or different from each other.

As an example, in the mathematical expression 1,PREAMBLE_RECEIVED_TARGET_POWER is a value set during the initial randomaccess preamble transmission, and may be considered as a target receivedpower when the base station receives the random access preamble. Sincethe NR UL band and the SUL use different frequency bands, they may havedifferent channel characteristics. Accordingly, the value ofPREAMBLE_RECEIVED_TARGET_POWER when Msg.1 is transmitted on the NR ULband and the value when Msg.1 is transmitted on the SUL may be differentfrom each other.

As another example, in the mathematical expression 1, P_(CMAX) (i) meansthe maximum transmitted power value that the terminal can use in thei-th subframe (or slot). The same maximum transmitted power value thatcan be used by the terminal may be used when Msg.1 is transmitted on theNR UL band and when Msg.1 is transmitted on the SUL.

As still another example, in the mathematical expression 1, PL is adownlink path loss value estimated by the terminal through the downlinksignal that the base station transmits to the downlink. In case oftransmitting Msg.1 on the NR UL band, the downlink path loss valueestimated by the terminal on the NR DL band may be used in themathematical expression 1. However, in case of the SUL band, there isnot the downlink band corresponding to the SUL, and thus the terminalmay reuse the downlink path loss value estimated on the NR DL band inthe mathematical expression 1. In this case, an error occurring due tothe different path loss values of the different channels may becompensated for using the offset value that the base station transmitsto the terminal through the RIVISI or OSI.

The operation of the base station for option 2-A as described above isillustrated in FIG. 5B. FIG. 5B is a diagram illustrating anotherexample of a base station operation for a terminal initial access in SULoperation scenarios according to various embodiments of the disclosure.In FIG. 5B, the base station transmits all the random access parameterson the NR UL band and the SUL band in operation 530. However, the basestation does not know whether the terminal will transmit Msg.1 on the NRUL band or the SUL. This is because the terminal determines this inaccordance with the quality of the NR DL band measured by the terminalitself as illustrated in FIG. 5A. Accordingly, the base station attemptsreception of Msg.1 with respect to all the NR UL band and the SUL inoperation 532. The base station having received Msg.1 transmits RARgrant and RAR (Msg.2) to the terminal through the NR DL band inoperation 534. Although not exemplified in FIG. 5B, the base station, asshown in operation 434 of FIG. 4B, may determine whether the UL carrieris changed, and may command band switching through the RAR grant and theRAR (Msg.2). The terminal having received this may transmit Msg.3 on theband commanded by the base station as shown in FIG. 4A. The base stationmay receive Msg.3 on the band commanded by the base station itself inoperation 536, and may transmit Msg.4 on the NR DL band in operation538.

Option 2-B) FIG. 6A is a diagram illustrating still another example of aterminal operation for a terminal initial access in SUL operationscenarios according to various embodiments of the disclosure. Asillustrated in FIG. 6A, the SUL may be used as a fallback mode. Morespecifically, the terminal having received all the random accessparameters in operation 602 for the NR UL band and the SUL from the basestation, calculates the transmitted power of the random access preamble(Msg.1) in operation 604, and transmits Msg.1 on the NR UL band inoperation 606. In this case, whether to transmit Msg.1 on the NR UL bandmay be determined by the terminal through the method of option 2-A asdescribed above, and the terminal may transmit Msg.1 as a default on theNR UL band by pre-engagement between the base station and the terminal.The transmitted power of Msg.1 may be calculated using the mathematicalexpression 1, and in this case, the path loss value of the NR DL bandmay be used as the path loss value. However, since the centerfrequencies of the NR DL band and the NR UL band are far apart from eachother, mismatch of the path loss values of the two bands may be great.Further, in an NR system using analog beamforming (e.g., hybridbeamforming), the beam used on the NR DL band and the beam used on theNR UL band may be different from each other. In this case, the mismatchof the path loss values of the two bands may be great. In this case, thebase station may notify the terminal of the path loss value that can beused in the mathematical expression 1 through the RMSI or OSI. On theother hand, the terminal having transmitted Msg.1 attempts reception ofthe RAR during RAR reception window (ra-ResponseWindowSize) configuredby the base station through the RMSI or OSI (receive Msg.2) in operation608. The terminal having succeeded in the reception of Msg.2 maytransmit Msg.3 on the NR UL band in operation 612. The terminal havingnot received Msg.2 in the corresponding window determines whether thenumber of transmissions of Msg.1 reaches the maximum value(preambleTransMax) in operation 610. If the number of transmissions ofMsg.1 on the NR UL band does not reach the maximum value, the terminalretransmits Msg.1 on the NR UL band. During the retransmission of Msg.1,the terminal may increase the transmitted power as much as the powerramping step size to transmit Msg.1 in operation 614. If the number oftransmissions of Msg.1 on the NR UL band reaches the maximum value, theterminal may end the random access operation on the NR UL band, and mayre-perform transmission of Msg.1 on the SUL. Since the channelcharacteristic on the NR UL band may be different from the channelcharacteristic of the SUL, the terminal may newly calculate thetransmitted power of Msg. 1 on the SUL in operation 616. Power rampingmay be performed in operation 618. In this case, the transmitted powervalue of Msg.1 may be calculated through the mathematical expression 1.In this case, parameter values for calculating the transmitted powervalue of Msg.1 transmitted on the NR UL band and parameter values forcalculating the transmitted power value of Msg.1 transmitted on the SULin the mathematical expression 1 may be equal to or different from eachother.

As an example, in the mathematical expression 1,PREAMBLE_RECEIVED_TARGET_POWER is a value set during the initial randomaccess preamble transmission, and may be considered as a target receivedpower when the base station receives the random access preamble. Sincethe NR UL band and the SUL use different frequency bands, they may havedifferent channel characteristics. Accordingly, the value ofPREAMBLE_RECEIVED_TARGET_POWER when Msg.1 is transmitted on the NR ULband and the value when Msg.1 is transmitted on the SUL may be differentfrom each other.

As another example, in the mathematical expression 1, P_(CMAX) (i) meansthe maximum transmitted power value that the terminal can use in thei-th subframe (or slot). The same maximum transmitted power value thatcan be used by the terminal may be used when Msg.1 is transmitted on theNR UL band and when Msg.1 is transmitted on the SUL.

As still another example, in the mathematical expression 1, PL is adownlink path loss value estimated by the terminal through the downlinksignal that the base station transmits to the downlink. In case oftransmitting Msg.1 on the NR UL band, the downlink path loss valueestimated by the terminal on the NR DL band may be used in themathematical expression 1. However, in case of the SUL band, there isnot the downlink band corresponding to the SUL, and thus the terminalmay reuse the downlink path loss value estimated on the NR DL band inthe mathematical expression 1. In this case, an error occurring due tothe different path loss values of the different channels may becompensated for using the offset value that the base station transmitsto the terminal through the RMSI or OSI.

The terminal having transmitted Msg.1 on the SUL attempts reception ofthe RAR during RAR reception window (ra-ResponseWindowSize) configuredby the base station through the RMSI or OSI (receive Msg.2) in operation620. The terminal having not received Msg.2 in the corresponding windowdetermines whether the number of transmissions of Msg.1 reaches themaximum value (preambleTransMax) in operation 622. If the number oftransmissions of Msg.1 on the SUL does not reach the maximum value, theterminal retransmits Msg.1 on the SUL. in operation 624, during theretransmission of Msg.1, the terminal may increase the transmitted poweras much as the power ramping step size to transmit Msg.1. ThepowerRampingStep for power ramping on the NR UL band andpowerRampingStep for power ramping on the SUL may be different from eachother. Further, the maximum number of transmissions (preambleTransMax)of Msg.1 on the NR UL band and the maximum number of transmissions(preambleTransMax) of Msg.1 on the SUL may be different from each other.If the number of transmissions of Msg.1 on the SUL reaches the maximumvalue, the terminal may end the random access operation on the SUL, andmay re-perform cell search in operation 626. The terminal havingsucceeded in the reception of Msg.2 on the SUL may transmit Msg.3 on theSUL in operation 628.

The operation of the base station for option 2-B as described above isillustrated in FIG. 6B. FIG. 6B is a diagram illustrating still anotherexample of a base station operation for a terminal initial access in SULoperation scenarios according to various embodiments of the disclosure.In FIG. 6B, the base station transmits all the random access parameterson the NR UL band and the SUL band in operation 630. However, the basestation does not know whether the terminal will transmit Msg.1 on the NRUL band or the SUL. This is because the terminal attempts transmissionof Msg.1 on the SUL as shown in operation 628 of FIG. 6A if transmissionof Msg.1 on the NR UL band has failed. Accordingly, the base stationattempts reception of Msg.1 with respect to all the NR UL band and theSUL in operation 632. The base station having received Msg.1 transmitsRAR grant and RAR (Msg.2) to the terminal through the NR DL band inoperation 634. Although not exemplified in FIG. 6B, the base station, asshown in FIG. 4B, may determine whether the UL carrier is changed, andmay command band switching through the RAR grant and the RAR (Msg.2).The terminal having received this may transmit Msg.3 on the bandcommanded by the base station as shown in FIG. 4A. The base station mayreceive Msg.3 on the band commanded by the base station itself inoperation 636, and may transmit Msg.4 on the NR DL band in operation638.

Option 2-C) As a modification of option 2-B as described above, theoperations of the base station and the terminal as illustrated in FIG.7A may be considered. FIG. 7A is a diagram illustrating yet stillanother example of a terminal operation for a terminal initial access inSUL operation scenarios according to various embodiments of thedisclosure. More specifically, the terminal having acquired all therandom access parameters for the NR UL band in operation 702, calculatesthe transmitted power of the random access preamble (Msg.1) in operation704, and the SUL band through the NR DL band may transmit Msg.1 on theNR UL band in operation 706. In this case, whether to transmit Msg.1 onthe NR UL band may be determined by the terminal through the method ofoption 2-A as described above, and the terminal may transmit Msg.1 as adefault on the NR UL band by pre-engagement between the base station andthe terminal. The transmitted power of Msg.1 may be calculated using themathematical expression 1, and in this case, the path loss value of theNR DL band may be used as the path loss value. However, since the centerfrequencies of the NR DL band and the NR UL band are far apart from eachother, mismatch of the path loss values of the two bands may be great.Further, in an NR system using analog beamforming (e.g., hybridbeamforming), the beam used on the NR DL band and the beam used on theNR UL band may be different from each other. In this case, the mismatchof the path loss values of the two bands may be great. In this case, thebase station may notify the terminal of the path loss value that can beused in the mathematical expression 1 through the RMSI or OSI. On theother hand, the terminal having succeeded in the reception of Msg.2within the RAR reception window size (ra-ResponseWindowSize) configuredby the base station in operation 708 may transmit Msg.3 on the NR ULband in operation 710. The terminal having failed in the reception ofMsg.2 within the RAR window size on the NR DL band in operation 708 mayre-perform the transmission of Msg.1 on the SUL based on the randomaccess parameters for the SUL configured by the base station through theRSMI or OSI in operation 714. Since the channel characteristics of theNR UL band and the SUL may be different from each other, the terminalmay re-calculate the transmitted power value for transmitting Msg.1 onthe SUL in operation 712. In this case, the transmitted power value ofMsg.1 may be calculated through the path loss value measured by theterminal on the NR DL band and preambleInitialReceivedTargetPower on theSUL configured by the base station through the RMSI or OSI. If thenumber of transmissions of Msg.1 on the SUL exceeds the maximum numberof transmissions configured by the base station in operation 716, theterminal may end the random access process, and may re-perform cellsearch in operation 718. If the number of transmissions of Msg.1 on theSUL does not exceed the maximum number of transmissions configured bythe base station, the terminal may perform retransmission of Msg.1 onthe SUL. In this case, the terminal may perform retransmission of Msg.1by increasing the transmitted power value of previous Msg.1 transmissionas much as the power ramping step size (powerRampingStep) in operation720.

The operation of the base station for option 2-C as described above isillustrated in FIG. 7B. FIG. 7B is a diagram illustrating yet stillanother example of a base station operation for a terminal initialaccess in SUL operation scenarios according to various embodiments ofthe disclosure. In FIG. 7B, the base station transmits all the randomaccess parameters on the NR UL band and the SUL band in operation 730.However, the base station does not know whether the terminal willtransmit Msg.1 on the NR UL band or the SUL. This is because theterminal attempts transmission of Msg.1 on the SUL as shown in FIG. 7Aif transmission of Msg.1 on the NR UL band has failed. Accordingly, thebase station attempts reception of Msg.1 with respect to all the NR ULband and the SUL in operation 732. The base station having receivedMsg.1 transmits RAR grant and RAR (Msg.2) to the terminal through the NRDL band in operation 734. Although not exemplified in FIG. 7B, the basestation, as shown in FIG. 4B, may determine whether the UL carrier ischanged, and may command band switching through the RAR grant and theRAR (Msg.2). The terminal having received this may transmit Msg.3 on theband commanded by the base station as shown in FIG. 4A. The base stationmay receive Msg.3 on the band commanded by the base station itself inoperation 736, and may transmit Msg.4 on the NR DL band in operation738.

The terminals having succeeded in the initial access transmit a datachannel (physical uplink shared channel (PUSCH), a control channel(physical uplink control channel (PUCCH)), and a sounding signal(sounding reference signal (SRS)) to the uplink. In this case, whetherto transmit the PUSCH, PUCCH, and SRS on the NR UL band or on the SULshould be investigated as the operations of the terminal and the basestation. For example, the base station may configure whether the PUSCH,PUCCH, and SRS should be transmitted on the NR UL band or on the SULthrough UE-specific RRC, MAC CE, or MAC message to the terminals havingsucceeded in the initial access (i.e., terminals in an RRC connectionstate). As another example, the base station may command activation anddeactivation of the NR UL band or the SUL through the MAC CE as shown inFIGS. 8A to 8C with respect to the terminals having succeeded in theinitial access (i.e., terminals in the RRC connection state).

FIG. 8A is a diagram illustrating an example of a media accesscontrol-control element (MAC CE) for activation/deactivation of a SUL inSUL operation scenarios according to various embodiments of thedisclosure. FIG. 8B is a diagram illustrating an example of a MAC CE fortransmission of a path loss value measured by a base station in a SUL inSUL operation scenarios according to various embodiments of thedisclosure. FIG. 8C is a diagram illustrating an example of a MAC CE foractivation/deactivation of a SUL and for transmission of a path lossvalue measured by a base station in an activated SUL in SUL operationscenarios according to various embodiments of the disclosure.

In this case, as shown in FIG. 8A, the MAC CE may command onlyactivation and deactivation of the NR UL band or the SUL. In FIG. 8A, C1to C5 correspond to 1-bit field (i.e., 5-bit in total), and mean 5 CCsused on the NR UL band. Further, S1 and S2 correspond to 1-bit field(i.e., 2-bit in total), and means two CCs used on the SUL. The term “R”means a reversed 1-bit field. For example, if C1 to C5 are composed of“10001”, the NR UL band means that CC #1 and CC #5 are activated, and CC#2, CC #3, and CC #4 are deactivated. In a similar manner, if S1 and S2are composed of “10”, SUL means that CC #1 is activated, and CC #2 isdeactivated. Although FIG. 8A illustrates an example in which the NR ULband is composed of 5 CCs, and the SUL is composed of 2 CCs, but are notlimited thereto.

On the other hand, the terminal may control the transmitted power of thePUSCH, PUCCH, and SRS transmitted to the uplink. In general, the uplinktransmitted power is controlled using transmitted power controlparameters configured by the base station and a downlink path lossmeasured by the terminal. However, since there is not the downlink bandcorresponding to the SUL, the terminal is unable to estimate the pathloss value during transmission of uplink PUSCH, PUCCH, and SRS on theSUL. Accordingly, as shown in FIG. 8B, the base station may transmit thepath loss value measured by the base station itself on the SUL throughthe MAC CE. Although FIG. 8B illustrates an example in which the SUL iscomposed of 2 CCs, and the base station transmit the path loss value forS1 and S2 to the terminal, it may be extended to an example in which theSUL is composed of 1 CC, or the SUL is composed of three or more CCs. Asanother example, as shown in FIG. 8C, the base station may commandactivation and deactivation of the CCs constituting the NR UL band orthe SUL, and may transmit UL path loss values of respective CCs (pathloss values measured by the base station) to the terminal at the sametime. Although FIG. 8C illustrates that the base station transmits tothe terminal only UL path loss values for all the CCs constituting theNR UL band and the SUL, the base station may not transmit the path lossvalues for the CCs constituting the NR UL band, but may transmit onlythe UL path loss values for the CCs constituting the SUL.

Although FIGS. 8B and 8C illustrate that the base station transmits theUL path loss value measured by the base station itself, the base stationmay transmit an offset value rather than the UL path loss value measuredby the base station itself. For example, consider FIG. 9. FIG. 9 is adiagram illustrating an example of a procedure in which a base stationtransmits to a terminal offset information between a downlink path lossvalue measured by the terminal and an uplink path loss value measured bythe base station according to various embodiments of the disclosure. Asillustrated in FIG. 9, the base station may transmit a downlink signalto the terminal in operation 902, and the terminal may estimate thedownlink path loss value using this in operation 904. In this case, thedownlink signal may be a downlink synchronization signal (SSS or DMRS ofSSS and PBCH), or downlink channel state information—reference signal(CSI-RS). Whether the terminal should estimate the path loss using thesynchronization signal or the CSI-RS may be configured by the basestation using the DCI, MAC CE, or RRC signaling. The terminal havingestimated the downlink path loss may set the transmitted power fortransmitting the PUSCH, PUCCH, and SRS transmitted by the terminalitself to the uplink using this.

On the other hand, the base station may estimate the uplink path lossusing the uplink signal transmitted from the terminal in operation 906.In this case, the uplink signal may be an SRS, random access preamble,or DMRS used to transmit uplink PUSCH/PUCCH. FIGS. 8A to 8C illustratethat a time point of operation 906 at which the uplink path loss of thebase station is estimated is after a time point of operation 904 atwhich the downlink path loss of the terminal is estimated, but is notlimited thereto. For example, the time point of operation 906 at whichthe uplink path loss of the base station is estimated may be before thetime point of operation 904 at which the downlink path loss of theterminal is estimated or after a time point of operation 910 at whichthe downlink path loss of the base station is estimated.

The terminal may transmit to the base station a power headroom valuethat means a difference between the transmitted power value used by theterminal itself for the uplink transmission and the maximum transmittedpower value Pmax,c of the terminal itself in operation 908. Further, inaddition to the power headroom value, the terminal may transmit to thebase station the maximum transmitted power value of the terminal itselfin operation 908. The base station may reversely estimate the downlinkpath loss value estimated by the terminal using the power headroom valuetransmitted from the terminal and Pmax,c value. Accordingly, the basestation may estimate the uplink path loss value through the uplink SRStransmitted by the terminal and the random access preamble, and maycalculate an offset between the downlink path loss value estimated bythe terminal and a predicted value of the downlink path loss value. Suchan offset value may be transmitted from the base station to the terminalthrough the MAC CE of FIGS. 8B and 8C in operation 912.

In the embodiments of the disclosure as described above, constituentelements included in the disclosure are expressed in a singular form orin a plural form. However, such a singular or plural expression isselected to suit a situation presented for convenience in explanation,and thus the disclosure is not limited to such singular or pluralconstituent elements. Even plural constituent elements may be expressedin a singular form, and even a single constituent element may beexpressed in a plural form.

FIG. 10 is a block diagram illustrating a structure of a terminalaccording to various embodiments of the disclosure.

As shown in FIG. 10, the terminal (also referred to as user equipment(UE) or mobile station (MS)) may include a transceiver 1010, acontroller 1020, and a storage 1030. In this disclosure, the controllermay be defined as a circuit, an application-specific integrated circuit,or at least one processor.

The controller 1020 may control the transceiver 1010 to receiveinformation for performing a random access from a base station,determine a frequency band to perform the random access between firstand second frequency bands based on the information for performing therandom access, and control the transceiver 1010 to transmit a randomaccess preamble on the determined frequency band.

The controller 1020 may measure a reference signal received power (RSRP)received from the base station, compare the RSRP with a threshold valueincluded in the information for performing the random access, determinethe first frequency band as the frequency band for performing the randomaccess if the RSRP is smaller than the threshold value, and determinethe second frequency band as the frequency band for performing therandom access if the RSRP is equal to or larger than the thresholdvalue.

The controller 1020 may identify a target received power parameter ofthe random access preamble corresponding to the first frequency bandfrom the information for performing the random access if the RSRP issmaller than the threshold value, and control the transceiver 1010 totransmit the random access preamble on the first frequency band based onthe target received power parameter of the random access preamblecorresponding to the first frequency band.

The controller 1020 may identify a target received power parameter ofthe random access preamble corresponding to the second frequency bandfrom the information for performing the random access if the RSRP isequal to or larger than the threshold value, and control the transceiver1010 to transmit the random access preamble on the second frequency bandbased on the target received power parameter of the random accesspreamble corresponding to the second frequency band.

The controller 1020 may control the transceiver 1010 to receiveinformation on transmission of a physical uplink control channel (PUCCH)from the base station on terminal-specific radio resource control (RRC)signaling, and control the transceiver 1010 to transmit the PUCCH on thefirst or second frequency band based on the information on thetransmission of the PUCCH.

The storage 1030 may store at least one of information transmitted orreceived through the transceiver 1010 and information generated throughthe controller 1020.

FIG. 11 is a block diagram illustrating a structure of a base stationaccording to various embodiments of the disclosure.

As shown in FIG. 11, the base station (also referred to as evolved NodeB (eNB), next generation Node B (gNB) or BS) may include a transceiver1110, a controller 1120, and a storage 1130. In this disclosure, thecontroller may be defined as a circuit, an application-specificintegrated circuit, or at least one processor.

The controller 1120 may generate information for performing the randomaccess in a first or second frequency band, control the transceiver 1110to transmit the generated information to a terminal, and control thetransceiver 1110 to receive a random access preamble for performing therandom access on the frequency band determined based on the generatedinformation.

The controller 1120 may control the transceiver 1110 to transmit to theterminal information on a frequency band related to transmission of aphysical uplink control channel (PUCCH) on terminal-specific radioresource control (RRC) signaling.

The storage 1130 may store at least one of information transmitted orreceived through the transceiver 1110 and information generated throughthe controller 1120.

While the disclosure has been described with reference to variousembodiments thereof, it will be understood t by those skilled in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the disclosure as defined by theappended claims and their equivalents.

What is claimed is:
 1. A method by a terminal for performing a randomaccess in a wireless communication system, the method comprising:receiving, from a base station, first information for configuring asupplementary uplink (SUL), second information for performing the randomaccess in an uplink (UL), and third information for performing therandom access in the SUL; detecting a physical downlink control channel(PDCCH) order based on downlink control information (DCI); determining acarrier for a physical random access channel (PRACH) transmission basedon the DCI; and transmitting, to the base station, the PRACHtransmission on the determined carrier, wherein the DCI includes anindicator for indicating the carrier between a first carrier and asecond carrier, and wherein the first carrier is associated with the ULand the second carrier is associated with the SUL.
 2. The method ofclaim 1, further comprising: identifying that a random access procedurecorresponding to the PRACH transmission is initiated based on the PDCCHorder.
 3. The method of claim 1, wherein the DCI further includesinformation on a contention-free random access.
 4. The method of claim3, wherein the indicator included in the DCI indicates which the carrierto transmit the PRACH transmission based on the information on thecontention-free random access and the first information for configuringthe SUL.
 5. The method of claim 1, wherein the second carrier is lowerthan the first carrier.
 6. A method by a base station for performing arandom access in a wireless communication system, the method comprising:transmitting, to a terminal, first information for configuring asupplementary uplink (SUL), second information for performing the randomaccess in an uplink (UL), and third information for performing therandom access in the SUL; transmitting, to the terminal, downlinkcontrol information (DCI) including an indicator for indicating acarrier between a first carrier and a second carrier; and receiving,from the terminal, a physical random access channel (PRACH) transmissionon the carrier, wherein a physical downlink control channel (PDCCH)order is detected based on the DCI, wherein the carrier is determinedfor the PRACH transmission based on the DCI, and wherein the firstcarrier is associated with the UL and the second carrier is associatedwith the SUL.
 7. The method of claim 6, wherein a random accessprocedure corresponding to the PRACH transmission is initiated based onthe PDCCH order.
 8. The method of claim 7, wherein the DCI furtherincludes information on a contention-free random access.
 9. The methodof claim 8, wherein the indicator included in the DCI indicates whichthe carrier to transmit the PRACH transmission based on the informationon the contention-free random access and the first information forconfiguring the SUL.
 10. The method of claim 6, wherein the secondcarrier is lower than the first carrier.
 11. A terminal for performing arandom access in a wireless communication system, the terminalcomprising: a transceiver; and a controller configured to: control thetransceiver to receive, from a base station, first information forconfiguring a supplementary uplink (SUL), second information forperforming the random access in an uplink (UL), and third informationfor performing the random access in the SUL, detect a physical downlinkcontrol channel (PDCCH) order based on downlink control information(DCI), determine a carrier for a physical random access channel (PRACH)transmission based on the DCI, and control the transceiver to transmit,to the base station, the PRACH transmission on the determined carrier,wherein the DCI includes an indicator for indicating the carrier betweena first carrier and a second carrier, and wherein the first carrier isassociated with the UL and the second carrier is associated with theSUL.
 12. The terminal of claim 11, wherein the controller is configuredto: identify that a random access procedure corresponding to the PRACHtransmission is initiated based on the PDCCH order.
 13. The terminal ofclaim 11, wherein the DCI further includes information on acontention-free random access.
 14. The terminal of claim 13, wherein theindicator included in the DCI indicates which the carrier to transmitthe PRACH transmission based on the information on the contention-freerandom access and the first information for configuring the SUL.
 15. Theterminal of claim 11, wherein the second carrier is lower than the firstcarrier.
 16. A base station for performing a random access in a wirelesscommunication system, the base station comprising: a transceiver; and acontroller configured to: control the transceiver to transmit, to aterminal via the transceiver, first information for configuring asupplementary uplink (SUL), second information for performing the randomaccess in an uplink (UL), and third information for performing therandom access in the SUL, control the transceiver to transmit, to theterminal via the transceiver, downlink control information (DCI)including an indicator for indicating a carrier between a first carrierand a second carrier, and control the transceiver to receive, from theterminal via the transceiver, a physical random access channel (PRACH)transmission on the carrier, wherein a physical downlink control channel(PDCCH) order is detected based on the DCI, wherein the carrier isdetermined for the PRACH transmission based on the DCI, and wherein thefirst carrier is associated with the UL and the second carrier isassociated with the SUL.
 17. The base station of claim 16, wherein arandom access procedure corresponding to the PRACH transmission isinitiated based on the PDCCH order.
 18. The base station of claim 16,wherein the DCI further includes information on a contention-free randomaccess.
 19. The base station of claim 18, wherein the indicator includedin the DCI indicates which the carrier to transmit the PRACHtransmission based on the information on the contention-free randomaccess and the first information for configuring the SUL.
 20. The basestation of claim 16, wherein the second carrier is lower than the firstcarrier.